In the next generation wideband wireless communication network, how to solve the inter-cell interference in the wireless communication network becomes one key factor of whether the User Terminal (UT) throughput among cells and the average UT throughput can be improved.
At present, the Institute of Electrical and Electronics Engineers (IEEE) 802.16j, the International Mobile Telecommunications-Advanced (IMT-Advanced) and the Wireless World Initiative New Radio (WINNER) put forward methods such as the interference randomization, interference coordination, and interference cancellation and so on to solve the problem of the inter-cell interference.
The LTE suggests dividing the coverage area of a certain cell into an inner layer and an outer layer according to the interference on the UTs of this cell induced by the adjacent cells of this cell. The inner layer is an area without inter-cell interference, and adopts full power compensation to solve the problem of inter-cell interference; and the outer layer is the area having the inter-cell interference, and adopts the part power control and path loss compensation to solve the problem of the inter-cell interference, wherein the part power control and path loss compensation belong to the interference coordination method.
Besides, the LTE suggests adopting the OI to indicate the interference state of the Physical. Resource Block (PRB) occupied by the UT which endures high level inter-cell interference and generate an OI report, transferring the OI report among different Base Stations (BSs) in the coverage range of the wireless communication network to negotiate the interference state of the PRB, and then adopting a certain measure to make the inter-cell interference on this PRB to be reduced efficiently, and finally achieving the object of coordinating the inter-cell interference, wherein the OI report is for indicating interference states of all the PRBs occupied by the UT.
The OI is defined by the LTE as follows: each PRB is configured with one OI value, and this OI value is classified into 3 levels 2, 1, and 0, which respectively represent that the current interference state of the PRB is high interference, middle interference and low interference; and each OI value is denoted by 2 bits, namely “10” represents the “high” interference, “01” represents the “middle” interference and “00” represents the “low” interference. The OI report is a set of the OI values of all the PRBs occupied by the UT. Since an OI value is denoted by a binary number, correspondingly, the OI report is also denoted by the binary number.
However, because 2 bits have four representation modes “11”, “10”, “01” and “00”, and can respectively represent four interference states, but the LTE only uses three interference states, so there is one state unused, which means the OI report doesn't have all the occupied bits fully used. However, the more number of bits is used, the more resources of the system are wasted, and the more system overhead is required.